Files
2026-06-26 00:25:59 +02:00

303 lines
8.6 KiB
C

#include "ch32v30x_rtc.h"
#include "lib/config.h"
#include "lib/monocypher/monocypher-ed25519.h"
#include "meshcore/meshframing.h"
#include "meshcore/packetstructs.h"
#include <string.h>
#include "advert.h"
#include "util/hexdump.h"
#include "lib/base64.h"
#include "util/log.h"
#define TAG "Advert"
static void build_ad_message (const FrameStruct *frame,
uint8_t *out,
size_t *out_len) {
size_t idx = 0;
// pubkey + timestamp (your 36 bytes)
memcpy (out + idx, frame->payload, 36);
idx += 36;
// rest of payload after signature region
memcpy (out + idx,
&frame->payload[100],
frame->payloadLen - 100);
idx += (frame->payloadLen - 100);
*out_len = idx;
}
void ed25519_sign_ad (FrameStruct *frame) {
uint8_t *signature = &frame->payload[36];
uint8_t message[256];
size_t m = 0;
// pubkey + timestamp (0..35)
memcpy (message + m, frame->payload, 36);
m += 36;
// skip signature [36..99]
// payload after signature
memcpy (message + m,
frame->payload + 100,
frame->payloadLen - 100);
m += frame->payloadLen - 100;
crypto_ed25519_sign (signature,
persistent.privkey,
message,
m);
}
int ed25519_verify_ad (const FrameStruct *frame) {
const uint8_t *signature = &frame->payload[36];
uint8_t message[256];
size_t m = 0;
if (signature[63] & 224)
return 0;
// pubkey + timestamp
memcpy (message + m, frame->payload, 36);
m += 36;
// skip signature [36..99]
// payload after signature
memcpy (message + m,
frame->payload + 100,
frame->payloadLen - 100);
m += frame->payloadLen - 100;
return crypto_ed25519_check (signature,
frame->payload, // pubkey at start
message,
m) == 0;
}
void sendAdvert (uint8_t shouldFlood) {
FrameStruct frame;
size_t offset = 0;
frame.header = (shouldFlood ? ROUTE_TYPE_FLOOD : ROUTE_TYPE_DIRECT) | PAYLOAD_TYPE_ADVERT | PAYLOAD_VERSION_0;
/* ---- public key ---- */
memcpy (frame.payload + offset, persistent.pubkey, 32);
offset += 32;
/* ---- timestamp ---- */
uint32_t timestamp = RTC_GetCounter();
memcpy (frame.payload + offset, &timestamp, sizeof (timestamp));
offset += sizeof (timestamp);
/* ---- reserve signature ---- */
uint8_t *signature_pos = frame.payload + offset;
offset += 64;
/* ---- build app data directly into payload ---- */
size_t app_start = offset;
uint8_t dataFlags = ADVERTISEMENT_FLAG_HAS_NAME;
if (persistent.nodeType == NODE_TYPE_CHAT_NODE)
dataFlags |= ADVERTISEMENT_FLAG_IS_CHAT_NODE;
else if (persistent.nodeType == NODE_TYPE_REPEATER)
dataFlags |= ADVERTISEMENT_FLAG_IS_REAPEATER;
else if (persistent.nodeType == NODE_TYPE_ROOM_SERVER)
dataFlags |= ADVERTISEMENT_FLAG_IS_ROOM_SERVER;
else if (persistent.nodeType == NODE_TYPE_SENSOR)
dataFlags |= ADVERTISEMENT_FLAG_IS_SENSOR;
frame.payload[offset++] = dataFlags;
if (dataFlags & ADVERTISEMENT_FLAG_HAS_LOCATION) {
memcpy (frame.payload + offset, &persistent.latitude, sizeof (persistent.latitude));
offset += sizeof (persistent.latitude);
memcpy (frame.payload + offset, &persistent.longitude, sizeof (persistent.longitude));
offset += sizeof (persistent.longitude);
}
/*
if (dataFlags & ADVERTISEMENT_FLAG_RFU1) {
memcpy(frame.payload + offset, &persistent.rfu1, sizeof(persistent.rfu1));
offset += sizeof(persistent.rfu1);
}
if (dataFlags & ADVERTISEMENT_FLAG_RFU2) {
memcpy(frame.payload + offset, &persistent.rfu2, sizeof(persistent.rfu2));
offset += sizeof(persistent.rfu2);
}
*/
if (dataFlags & ADVERTISEMENT_FLAG_HAS_NAME) {
size_t nameLen = strlen (persistent.nodeName);
memcpy (frame.payload + offset, persistent.nodeName, nameLen);
offset += nameLen;
}
size_t app_len = offset - app_start;
frame.payloadLen = offset;
/* ---- sign directly over payload ---- */
ed25519_sign_ad (&frame);
/* ---- debug ---- */
hexdump ("Public key", frame.payload, 32);
hexdump ("Signature", signature_pos, 64);
hexdump ("Appdata", frame.payload + app_start, app_len);
iprintf ("Timestamp is %lu\n", timestamp);
iprintf ("NodeName %s\n", persistent.nodeName);
/* ---- send ---- */
frame.payloadLen = offset;
frame.path.pathLen = 0;
LoRaTransmit (&frame);
}
void decodeAdvertisement (const FrameStruct *frame) {
AdvertisementPayload advert;
memset (&advert, 0, sizeof (advert));
advert.valid = 0;
if (frame->payloadLen < 101) {
MESH_LOGW (TAG, "Advertisement frame too short (%d < 101)", frame->payloadLen);
return;
}
if (!ed25519_verify_ad (frame)) {
MESH_LOGW (TAG, "Incorrect signature");
return;
} else {
MESH_LOGI (TAG, "Advertisement signature ok.");
}
advert.valid = 1;
unsigned char index = 0;
memcpy (advert.pubKey, frame->payload + index, 32);
index += 32;
memcpy (&advert.timestamp, frame->payload + index, 4);
index += 4;
memcpy (advert.signature, frame->payload + index, 64);
index += 64;
advert.dataFlags = frame->payload[index++];
uint8_t expectedLen = 101;
if (advert.dataFlags & ADVERTISEMENT_FLAG_HAS_LOCATION) {
expectedLen += 8;
}
if (advert.dataFlags & ADVERTISEMENT_FLAG_RFU1) {
expectedLen += 2;
}
if (advert.dataFlags & ADVERTISEMENT_FLAG_RFU2) {
expectedLen += 2;
}
if (frame->payloadLen < expectedLen) {
MESH_LOGW (TAG, "Advertisement frame with data too short (%d < %d)", frame->payloadLen, expectedLen);
return;
}
if (advert.dataFlags & ADVERTISEMENT_FLAG_HAS_LOCATION) {
memcpy (&advert.latitude, frame->payload + index, 4);
index += 4;
memcpy (&advert.longitude, frame->payload + index, 4);
index += 4;
}
if (advert.dataFlags & ADVERTISEMENT_FLAG_RFU1) {
memcpy (&advert.rfu1, frame->payload + index, 2);
index += 2;
}
if (advert.dataFlags & ADVERTISEMENT_FLAG_RFU2) {
memcpy (&advert.rfu2, frame->payload + index, 2);
index += 2;
}
unsigned char nameLen = frame->payloadLen - index;
if (nameLen > 31) {
nameLen = 31; // leave space for null
}
memcpy (advert.nodeName, frame->payload + index, nameLen);
advert.nodeName[nameLen] = 0;
printAdvertisement (&advert);
saveAdvert (&advert);
}
void saveAdvert (const AdvertisementPayload *advert) {
NodeEntry *node = getNode (advert->pubKey[0]);
if (node == NULL) {
node = getNextNode();
memset (node, 0, sizeof (NodeEntry));
}
memcpy (node->name, advert->nodeName, sizeof (node->name));
memcpy (node->pubKey, advert->pubKey, sizeof (node->pubKey));
// -------------------------------
// Ed25519 ¡ú X25519 conversion
// -------------------------------
uint8_t peer_x[32];
crypto_eddsa_to_x25519 (peer_x, advert->pubKey);
// -------------------------------
// IMPORTANT: derive correct scalar
// (THIS fixes your HMAC mismatch)
// -------------------------------
uint8_t scalar[64];
uint8_t scalarOut[32];
crypto_sha512 (scalar, persistent.privkey, 32);
crypto_eddsa_trim_scalar (scalarOut, scalar);
// -------------------------------
// X25519 Diffie-Hellman
// -------------------------------
crypto_x25519 (node->secret,
scalarOut,
peer_x);
node->gps_latitude = advert->latitude;
node->gps_longitude = advert->longitude;
// add path
node->type = advert->dataFlags & 0x0F;
node->last_seen_lt = RTC_GetCounter();
node->last_seen_rt = advert->timestamp;
}
void printAdvertisement (const AdvertisementPayload *advert) {
iprintf (
"%s on %ld with type %s on %s location %ld %ld\n",
advert->dataFlags & ADVERTISEMENT_FLAG_HAS_NAME
? advert->nodeName
: "nameless node",
advert->timestamp,
(advert->dataFlags & 0x07) == 0x04 ? "sensor"
: (advert->dataFlags & 0x07) == 0x03 ? "room server"
: (advert->dataFlags & 0x07) == 0x02 ? "repeater"
: "chat node",
advert->dataFlags & 0x80 ? "known" : "unknown",
advert->latitude,
advert->longitude);
hexdump ("Public key", advert->pubKey, 32);
hexdump ("Signature", advert->signature, 64);
}